Is there any way to downgrade to iOS 14.4 from 14.6, where 14.4 is unsigned version now ?

I accidentally update my iPhone 6s to latest version iOS 14.6

The problem is my Xcode 12.4 MacOS Catalina does not support to this version for testing apps

and I need to test iOS app on my phone

and also unfortunately Mac book pro mid 2012 stop further updates

I searched a lot but can't find any solution.